Glycosyltransferase Family 38

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• Author: ^^^Warren Wakarchuk^^^
• Responsible Curator: ^^^Warren Wakarchuk^^^

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Glycosyltransferase Family GT38
Clan	GT-B
Mechanisn	inverting
Active site residues	known
CAZy DB link
https://www.cazy.org/GT38.html

Substrate specificities

Members of GT-38 are the bacterial polysialyltransferases (polySTs), which catalyze the addition of sialic acids from the activated sugar donor, CMP-sialic acid (CMP-Neu5Ac), to the nonreducing end of the growing polySia chain [1]. These enzymes build the polymer as a capsular polysaccharide on a specialized poly-β-KDO modified lyso-phosphatidyl glycerol anchor in the membrane of Gram negative bacteria [2]. . Bacterial polySia capsules exist in three different flavours: Escherichia coli K1, Neisseria meningitidis serotype B, Moraxella nonliquefaciens, and Mannheimia haemolytica A2 synthesize α-2,8-linked polySia whereas N. meningitidis serotype C produces a α-2,9-linked polymer and E. coli K92 produces polymers with alternating α-2,8 and α-2,9 linkages [3][4]<Glode1977. The molecular mimicry of these bacterial polySia capsules represents an elegant strategy to evade the host’s immune recognition since they are not considered as foreign. In addition, they confer a physical barrier protecting the pathogen from killing by the complement system [5].

Kinetics and Mechanism

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Catalytic Residues

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Three-dimensional structures

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Family Firsts

First stereochemistry determination

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First catalytic nucleophile identification

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First general acid/base residue identification

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First 3-D structure

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References

1. Cho JW and Troy FA 2nd. (1994). Polysialic acid engineering: synthesis of polysialylated neoglycosphingolipids by using the polysialyltransferase from neuroinvasive Escherichia coli K1. Proc Natl Acad Sci U S A. 1994;91(24):11427-31. DOI:10.1073/pnas.91.24.11427 |
2. Willis LM, Stupak J, Richards MR, Lowary TL, Li J, and Whitfield C. (2013). Conserved glycolipid termini in capsular polysaccharides synthesized by ATP-binding cassette transporter-dependent pathways in Gram-negative pathogens. Proc Natl Acad Sci U S A. 2013;110(19):7868-73. DOI:10.1073/pnas.1222317110 |
2. Willis LM, Stupak J, Richards MR, Lowary TL, Li J, and Whitfield C. (2013). Conserved glycolipid termini in capsular polysaccharides synthesized by ATP-binding cassette transporter-dependent pathways in Gram-negative pathogens. Proc Natl Acad Sci U S A. 2013;110(19):7868-73. DOI:10.1073/pnas.1222317110 |
3. Puente-Polledo L, Reglero A, González-Clemente C, Rodríguez-Aparicio LB, and Ferrero MA. (1998). Biochemical conditions for the production of polysialic acid by Pasteurella haemolytica A2. Glycoconj J. 1998;15(9):855-61. DOI:10.1023/a:1006902931032 |
4. Devi SJ, Schneerson R, Egan W, Vann WF, Robbins JB, and Shiloach J. (1991). Identity between polysaccharide antigens of Moraxella nonliquefaciens, group B Neisseria meningitidis, and Escherichia coli K1 (non-O acetylated). Infect Immun. 1991;59(2):732-6. DOI:10.1128/iai.59.2.732-736.1991 |

5. pmid= 8884739

6. Glode MP, Robbins JB, Liu TY, Gotschlich EC, Orskov I, and Orskov F. (1977). Cross-antigenicity and immunogenicity between capsular polysaccharides of group C Neisseria meningitidis and of Escherichia coli K92. J Infect Dis. 1977;135(1):94-104. DOI:10.1093/infdis/135.1.94 |
7. Lindhout T, Bainbridge CR, Costain WJ, Gilbert M, and Wakarchuk WW. (2013). Biochemical characterization of a polysialyltransferase from Mannheimia haemolytica A2 and comparison to other bacterial polysialyltransferases. PLoS One. 2013;8(7):e69888. DOI:10.1371/journal.pone.0069888 |
8. Willis LM, Gilbert M, Karwaski MF, Blanchard MC, and Wakarchuk WW. (2008). Characterization of the alpha-2,8-polysialyltransferase from Neisseria meningitidis with synthetic acceptors, and the development of a self-priming polysialyltransferase fusion enzyme. Glycobiology. 2008;18(2):177-86. DOI:10.1093/glycob/cwm126 |
9. Wheeler DC, Smith B, and Walls J. (1986). Substitution of aluminium salts by magnesium salts in control of dialysis hyperphosphataemia. Lancet. 1986;1(8494):1380. DOI:10.1016/s0140-6736(86)91687-9 |